Aluminum Windows

Sometimes it seems like half the houses and apartments out there have aluminum windows. Some of them are
single-paned and some are double-paned. The double-paned windows are better of course because they
have some insulation value. Typically though, a good percentage of them have moisture between the
panes which mean that the windows have failed and have to be replaced. The only good thing about the
single-paned windows is that they don’t have a seal to break.

When thinking about replacing aluminum windows, first consider the overall value of the project. If it’s
for a rental, try to use the working aluminum windows as long as possible, replacing them as needed or
as they fail. The same for a low to mid-range fix and flip. You may not be able to get the value out of the
property to pay for the new windows. Another situation where it doesn’t make a ton of sense to replace
windows is on an older house that doesn’t have any insulation in the walls unless you intend to also
insulate the walls. There’s no point in having insulated windows without insulated walls.

On a mid-range and up fix and flip you should budget in window replacement because it will be expected
for that kind of a property and the property should pay you back for replacing the windows.

The standard replacement windows are vinyl windows. These windows are economical and they perform
well. They will always be at least double-paned and have insulation value. The two main types of vinyl
windows are new construction and replacement windows. There’s little difference in the cost of the
windows themselves but there is a big difference in the cost of installation.

New construction windows have nail fins all around them that require the contractor to remove the trim,
siding, moisture barrier and flashing from around each window in order to remove and replace the
entire window. Then the barrier, trim and new flashing have to be carefully replaced and then caulked.
This can take four or more hours per window.

The other way is to use replacement windows. With replacement windows, the contractor removes the
moveable part of the window and then cuts out the center mullion of the aluminum window but leaves
the rest of the frame intact. S/he then removes the fixed glass and inserts the replacement window
through the remaining aluminum frame and seals it. This takes about an hour.

Replacement windows can easily be installed where there is flat trim around the windows. They can also
be installed into single-hung wood window frames. The most difficult situation for replacement windows
is where lap siding runs straight into the existing window frame (without exterior trim). In this situation
the flanges don’t have a solid flat surface to seal to.

With a 15 window house using an average material cost of $200 per window, the new construction
windows installed would cost about $400 each for a total of $6,000. The installed replacement windows
would cost about $250 each for a total of $3,750. Which number do you like better?


Today's guest blog is by Brian Sorensen, general contractor and member of the Real Estate Association of Puget Sound. His company, Unity Construction LLC, is a full-service residential
construction company in Puget Sound. His construction company invests in single
and multi-family properties.